Detergent formulators are faced with the task of devising products to remove a broad spectrum of soils and stains from fabrics. Chemically and physico-chemically, the varieties of soils and stains ranges the spectrum from polar soils, such as proteinaceous, clay, and inorganic soils, to non-polar soils, such as soot, carbon-black, by-products of incomplete hydrocarbon combustion, and organic soils. Detergent compositions have become more complex as formulators attempt to provide products which handle all types concurrently.
Formulators have been highly successful in developing traditional dispersants which are particularly useful in suspending polar, highly charged, hydrophilic particles such as clay. As yet, however, dispersents designed to disperse and suspend non-polar, hydrophobic-type soils and particles have been more difficult to develop. Surprizingly, it has recently been discovered that the .modified polyamines of the present invention are capable of mediating the re-depositon of non-polar soils
In addition, a wide variety of soil release agents for use in domestic and industrial fabric treatment processes such as laundering, fabric drying in hot air clothes dryers, and the like are known in the art. Various soil release agents have been commercialized and are currently used in detergent compositions and fabric softener/antistatic articles and compositions. Such soil release polymers typically comprise an oligomeric or polymeric ester "backbone".
Soil release polymers are generally very effective on polyester or other synthetic fabrics where the grease, oil or similar hydrophobic stains spread out and form a attached film and thereby are not easily removed in an aqueous laundering process. Many soil release polymers have a less dramatic effect on "blended" fabrics, that is on fabrics that comprise a mixture of cotton and synthetic material, and have little or no effect on cotton articles. The reason for the affinity of many soil release agents for synthetic fabric is that the backbone of a polyester soil release polymer typically comprises a mixture of terephthalate residues and ethyleneoxy or propyleneoxy polymeric units; the same materials that comprise the polyester fibers of synthetic fabric. This similar structure of soil release agents and synthetic fabric produce an intrinsic affinity between these compounds.
It has now been surprisingly discovered that in addition to the ability to mediate hydrophobic soil redeposition, certain polyamines act in concert with selected cationic surfactants to provide increase fabric soil removal, especially from cotton fabrics. This increased soil removal benefit has been found to be independent of the type of soil present on the cotton fabric.
The modified polyamine/cationic surfactant combinations of the present invention have the increased benefit of being compatible with hypochlorite and oxygen "peracid" bleaching agents. This is especially important in the area of surface active agents that are effective on non-colored cotton fabric. The hydrophilic cellulosic composition of cotton fabric presents a surface that is not compatible with the traditional polyester terephthalate-based soil release agents. Indeed, the polyamines of the present invention themselves exhibit a propensity for attachment to the surface of the cotton fabric.
The C.sub.12 -C.sub.14 dimethyl hydroxyethyl quaternary ammonium salts which serve as cationic surfactants for the purposes of the present invention, combine with the modified polyamine surface agent/dispersents to remove soils from fabric surfaces. This combination of materials also acts to prevent redeposition of soil by holding the soil suspended in the laundry liquor which is removed prior to rinsing.
It is a purpose of the present invention to provide laundry detergent compositions which combine C.sub.12 -C.sub.14 dimethyl hydroxyethyl quaternary ammonium cationic surfactants with modified polyamine dispersants.
It is a further object of the present invention to combine the C.sub.12 -C.sub.14 dimethyl hydroxyethyl quaternary ammonium cationic surfactant and polyamine dispersents with non-cotton soil release agents. This combination of ingredients provides a soil release benefit to all laundered fabric as well as the increase in cleaning capacity.
It is yet a further purpose of the present invention to provide a bleach stable cationic surfactant/polyamine dispersent composition.
A further purpose of the present invention is to provide a method for laundering soiled fabric which comprises the step of contacting the soiled fabric, especially cotton, with a laundry detergent composition containing C.sub.12 -C.sub.14 dimethyl hydroxyethyl quaternary ammonium cationic surfactants and the disclosed polyamines.